code: def test_register_ray():
      register_ray()
      assert "ray" in joblib.parallel.BACKENDS
      assert not ray.is_initialized()
  
imports: import joblib
  import sys
  import time
  import os
  import pytest
  from unittest import mock
  import pickle
  import numpy
  from sklearn.datasets import load_digits, load_iris
  from sklearn.model_selection import RandomizedSearchCV
  from sklearn.ensemble import ExtraTreesClassifier
  from sklearn.ensemble import RandomForestClassifier
  from sklearn.kernel_approximation import Nystroem
  from sklearn.kernel_approximation import RBFSampler
  from sklearn.pipeline import make_pipeline
  from sklearn.svm import LinearSVC, SVC
  from sklearn.tree import DecisionTreeClassifier
  from sklearn.linear_model import LogisticRegression
  from sklearn.neural_network import MLPClassifier
  from sklearn.model_selection import cross_val_score
  from ray.util.joblib import register_ray
  import ray
label_desc: Use image node_id 1 for calling a global function with example usage: test_register_ray() without return types